1. Field of the Invention
This invention relates to a novel video camera, and particularly to a video camera having an integral transverse tilt detector and a transverse tilt indicator that is viewable in the viewfinder of the camera.
2. Description of the Prior Art
A video camera comprises an optical-to-electronic conversion means having a longitudinal optical axis. The conversion means may include an optical system which focuses an image on the target or targets of one or more pickup tubes. The pickup tube or tubes generate electronic signals which are processed by associated circuitry to produce video signals usable in a particular video system to produce video images. The longitudinal optical axis is the axis through the center of the optical system. The transverse direction is normal to the longitudinal axis and parallels the horizontal lines and/or horizon line desired in the optical image incident on the target or targets.
Some video cameras are portable and, because of their size and weight, are carried on a shoulder rest on the camera operator's shoulder in such manner that the eyepiece of the camera's viewfinder is opposite the operator's right eye. The viewfinder is a closed, dark chamber containing a small video picture tube having a viewing screen which displays a video image that is a reproduction of the image that is incident on the target or targets of the pickup tube or tubes. The area adjacent to the screen of the picture tube contains various indicators. Both the picture tube and the adjacent indicator area are viewable through the eyepiece of the viewfinder.
The camera operator's attention is concentrated on what he sees in the viewfinder. Frequently, the operator would like to know whether the transverse direction of the camera is level, or is tilted from horizontal. Matching horizontal lines in the video image with the top or bottom edge of the picture-tube bezel yields inaccurate results. A transverse tilt indicator that displays the actual degrees from level or from the horizon gives more information than the operator needs. An indicator that provides a marker on a scale requires interpretation by the operator and too much of the operator's attention. Both such indicators and their associated detectors are complex and expensive. What is needed is a transverse tilt indicator, and an associated transverse tilt detector, which is simple and inexpensive to integrate into the camera, and provides an adequate amount of information with respect to the transverse tilt of the camera.